海鳗消化道的显微结构

采用大体解剖和光镜技术研究了海鳗(Muraenesax cinereius)消化道形态学和组织学。海鳗消化道分化为明显的食道、胃和肠。食道皱襞多且粗大，黏膜为复层上皮，部分区域为单层柱状上皮。上皮中含两种类型的杯状细胞，以杯状细胞层次多为显著特征，此外还有嗜酸性细胞。肌层厚。浆膜中纤维发达，伸人肌层并与黏膜下层相连。胃“Y”形，分为贲门部、盲囊部和幽门部，盲囊部发达。胃上皮为单层柱状上皮，贲门部和盲囊部胃腺发达，至幽门部胃腺逐渐消失。肠短，由具微绒毛的单层柱状上皮构成，小肠前段绒毛分支多且相互吻合，毛细血管丰富，平滑肌多。直肠单层柱状上皮与假复层纤毛柱状上皮共存。海鳗消化道组织结构特点反映了其凶猛、食肉、食量大的食性特点。

Microscopic structures of digestive tract in pike eel Muraenesox cinereius

By using light microscopes,it is detected that the digestive tract of the pike eel (Muraenesox cinereius) consists of distinguishable oesophagus,stomach and intestine.There are numerous large plicae in the oesophagus.Most area of the mucosa is covered by multi-layer squamous epithelium,while some local area is single-layered columnar epithelium.The epithelium,consisting of two types goblet cells,is characterized by the multitude of the goblet layers.In addition,it is found that there are some acidophilic cells distributed in the oesophagus epithelium near the basal cell.The muscularis externa of the oesophagus is thick.In the serosa,a large amount of fibers extend to the muscularis and connect with the submucosa.The Y-shaped stomach is divided into cardiac part,caecum gastricum and pyloric part.The caecum gastricum is well developed.In histology,the epithelium of stomach is constituted by single-layer columnar epithelium,under which,in the cardiac part and caecum gastricum,developed gastric glands present.The intestine is short.Its epithelium is composed of columnar cells with distinct microvilli.In the front part of intestine,the villi anastomose each other by their large number of branches.The capillary and smooth muscle fibers are abundant.The rectum mucosa epithelium is composed of single-layer columnar epithelium and pseudostratified ciliated columnar epithelium.Histological features of the digestive tract are consistent with the carnivorous habit of the pike eel.